Are images in a page stored to SB localStorage for offline use?

I'm using SB 2.10 as a PWA on Android with Chrome. If I navigate to a page with text and some images while connected to Wi-Fi, I can tap on the "eye" icon and view the image with resize capability. But if I stay on the page, turn on Airplane mode, wait for the top bar to become light yellow, and then tap the eye icon of those images, I get a red notification that says "Failed to navigate: Not found". Does this mean that SB doesn't store/cache images to LocalStorage?

(The reason I'm asking is that I'm going kayak camping somewhere with spotty cell coverage and I included a JPEG of the lake and campsites on the SB page where I have my camping gear checklist. Since I might be out of cell coverage while on the water I'm afraid I might not have access to the map.)

See Sync

By default all your pages are synced, but [[Document]] are not. They are fetched on demand. If you would also like to sync documents (so you can access them when offline), you can do so by setting the following in a Space Lua block in [[CONFIG]]:

config.set("sync.documents", true)

Or in Configuration Manager:

Refresh the page (close and reopen the app) while you are connected to your server after setting this option. I was not able to get it to apply with System: Reload and Sync: Space commands.

Thanks @henrikx, that's exactly what I needed and works perfectly!